(Fries, 1823)
Body
Large larvae with a length up to 20 mm. Living larvae are brownish. Fringe of swimming hairs present (Wiederholm, 1983; Moller Pillot, 1984a)
Head
The head length is 1.3 - 1.4 mm, about 1.5 times as long as wide with a cephalic index of 85-95% (Moller Pillot, 1984a)
Antenna
The antennal ratio is about 7. The ring organ is situated at 0.7 - 0.8 of the height of the first segment (Wiederholm, 1983; Moller Pillot, 1984a).
Mentum
Dorsomentum with 13 - 14 teeth on each side Ana mentum9 (Wiederholm, 1983).
Ligula and paraligula
Ligula with 5 brown teeth in a concave row. Paraligula with two broad teeth Ana ligula paraligula.
Mandible
The mandible has two small inner teeth Ana mandible.
Maxilla
The maxilla is short with one basal segment
Anal tubules
4 anal tubules which are longer than wide.
Posterior parapods
No teeth on the inner margin of the claws.
Differential characteristics
In the tribe of the Macropelopiini, Anatopynia differs from the other genera by the large (13 - 14) number of teeth on the dorsomentum Ana mentum9. Also the length of the full grown larvae exceeds the length of the related genera Macropelopia and Apsectrotanypus.